Contamination of the Deep Tissues of Carcasses by Bacteria Present on the Slaughter Instruments or in the Gut

Possible routes by which bacteria might reach the deep tissues of carcasses were tested by placing genetically ‘marked’strains of Escherichia coli, Clostridium perfringens or Bacillus thuringiensis on slaughter instruments before use and examining deep tissue samples for their presence post mortem . Bacteria present on the captive bolt pistol were recovered from the spleens of beef cattle and those placed on the pithing rod were found in both spleen and muscle of the flank and neck. Bacteria from the throat cutting (‘stick’) knife were isolated, on different occasions, from the heart, lung, spleen, liver and kidneys of sheep though rarely from their muscles. Orally administered bacteria were found in the spleen and lung, but not the musculature, of pigs.